The CEM LOW PASS 29B is a 24dB 4 pole low pass filter based on the CEM 3328 filter IC. Usually we don't offer custom IC designs but in this case the sound was worth it.

One of the main distinguishing capabilities of this filter is the switchable volume compensation for high resonance settings.

Most LPF suffer from a 12dB drop in pass band level at high resonance. The CEM 3328 IC has built-in provisions for overriding this limitation.

The result is a powerful sound even with high res.

Switchable 0dB or standard -12dB volume compensation

Input 1-3 On board 3 to 1 mixer combines signals patched to the filter The LEVEL pot controls the amount of attenuation from the mixer

1V/Oct Input
Exponential converters track linear voltage input at 1 volt per octave. This input is primarily used for keyboard tracking and pitch control of filter in self-oscillation mode.

CV Input 1
Control Voltage input with attenuator to control the depth of frequency modulation. When the knob is centered no modulation occurs. Positioning the knob to the left of zero inverts the incoming voltage (negative) and to the right the voltage is non-inverted (positive).

CV Input 2
Secondary Control Voltage input with attenuator. CV inputs are used to control the filters cutoff point. The most common input signal would be from an envelope generator or LFO.

Resonance Control
This knob varies the height of the resonant peak at the cutoff frequency of the filter.

Resonance CV
CV input to control the resonance amount with an attenuator to control depth of modulation

Wide-range lowpass filter with variable-height
resonant peak at cutoff frequency.
4 pole response
24db/oct cutoff slope
Range:Continuously variable from 35Hz-20kHz
Input impedance: 50K ohms
Output impedance: 1k ohms
Control Sens: 1 volt per octave